One conventional switch device includes an operating member mounted on a casing for movement along the casing. A switch means is provided and may be opened or closed in response to the movement of the operating member when it is depressed. A return spring is provided for biasing the operating member in the inoperative, or initial, position. A cam groove having a generally heart-shaped loop is formed in either the operating member or the casing. A lock member formed from a torsion coil spring is mounted at one end of the operating member or casing whichever does not support the cam groove. The free end of the torsion coil spring is received in the cam groove for movement along the groove.
Typically, when the operating member of such a conventional switch device is depressed, the free end of the torsion coil spring is moved and secured into a retaining portion of the cam groove in locked engagement. Thus, the operating member is held in the operative position when the switch means is in the closed, or activated, condition. When the operating member is subsequently depressed, the free end of the lock member is released from locked engagement with the retaining portion of the cam groove. As a result, the operating member is returned to the inoperative, or initial, position subject to the bias force of the return spring.
It has become popular to fabricate conventional switch devices in a compact construction. Accordingly, a compact lock means is desired having a cam groove and a lock member. However, the presence of the torsion coil spring lock member of the conventional design has rendered the achievement of a compact lock means impossible.
In an effort to solve this difficulty, a generally U-shaped wire has been used as a lock member, or pin, wherein one end of the lock pin may move along the cam groove. This arrangement, however, is not sufficient because one end of the lock pin often extends past the retaining portion of the cam groove thereby avoiding successful capture in the retaining portion of the cam groove. The lock pin utilized by the present invention allows for the compact manufacture of a quality switch device having improved positioning precision.